What '60 Minutes' Still Isn't Saying About The 'Miracle' Glioblastoma Drug

Last night, the hit
CBS news program 60 Minutes revisited a trial at Duke University that it had devoted two segments to early last year. Scientists at Duke are testing a modified form of the polio virus to treat glioblastoma, and the reason for the 60 Minutes update was that the research has recently been granted “breakthrough” status by the FDA—which may shave some time off the development pathway. The development of engineered viruses, or “oncolytic viruses,” to treat cancer is one type of immunotherapy that’s generating excitement in oncology circles.

The breakthrough status for Duke is good news, to be sure. Median survival for patients with glioblastoma who are treated with traditional chemotherapy is only about 14 months and two-year survival is 30%, according to the American Brain Tumor Association. The disease claims 12,000 people per year in the U.S. and was to blame for the death of Vice President Joe Biden’s son. Biden is now leading the government’s cancer “moonshot” initiative, and as part of that he visited Duke, where he met the first patient treated with the virus, Stephanie Lipscomb, who entered the trial in 2012 and is still cancer-free.

But winning breakthrough status from the FDA doesn’t guarantee that any treatment is actually a breakthrough. The Duke team has plenty of hurdles to overcome before the modified virus can become an approved treatment. In fact, the 60 Minutes segment revealed that one of the patients hailed as a miracle in last year's broadcast, Nancy Justice, suffered a recurrence of her brain tumor and died on April 6 at age 60.

And it’s important to remember that Justice, Lipscomb and the other 19 patients treated so far were in a Phase I trial in which eight patients have died, three have achieved long-term remissions and the rest are still being monitored. That means it’s too early to judge how the virus will perform in a larger patient population.

Here are some other key points to keep in mind about Duke’s cancer-fighting polio virus.

Polio is not the only virus that's been shown to work against cancer. Several companies and academic groups are testing a variety of engineered viruses to fight cancer, including herpes, vaccinia (cowpox) and adenovirus. And in October, the first virus-based drug was approved by the FDA,
Amgen’s Imlygic (talimogene laherparepvec, or T-VEC) for the treatment of melanoma. It’s an engineered form of the herpes virus that’s injected straight into melanoma tumors, where it kills cancer cells directly and also recruits immune-boosting cells to the tumors to boost its potency. It’s far from a miracle—studies show that it works best in a small subset of patients who are in Stage III of the disease, but overall it improves survival by only a few months—which is likely why the FDA declined to fast-track the drug to market last year.

Gliomas including glioblastoma are among the toughest cancers to beat. (Credit: Shutterstock)

But Amgen is still investigating Imlygic in different settings, which brings us to our next point…

Engineered viruses may work better in combo treatments than they do alone. The 60 Minutes update introduced viewers to Brendan Steele, another participant in the Duke trials who went into remission after being treated with the modified polio virus. Seven months later, his cancer returned, so his doctors gave him a dose of chemotherapy. Oddly, his brain tumor melted away after that, even though he had not responded well to chemotherapy prior to receiving the virus.

Steele’s reaction led Duke’s researchers to surmise that the immune response prompted by the virus may actually boost the effectiveness of chemotherapy. This idea is gaining steam among researchers and there are now trials underway combining oncolytic viruses with other treatments.

In the case of Imlygic, it is currently in a late-stage clinical trial in melanoma in combination with another type of immunotherapy,
Merck’s Keytruda (pembrolizumab), which inhibits the immune “checkpoint” PD-1. In an early trial, 56% of patients responded well to the treatment and two went into complete remissions—better results than had previously been seen with either drug alone.

Just because polio kills tumor cells in the test tube doesn’t mean it works in people. Towards the end of the two-segment 60 Minutes feature, correspondent Scott Pelley told viewers that “in the laboratory” the engineered polio virus killed cancers of the skin, lung, stomach and more. He then had one of the researchers show how it caused a breast tumor from a mouse to shrink. Seeing as the polio virus has not even moved into late-stage testing in people with glioblastoma, it seems premature to start declaring the treatment to be a cure-all for so many cancers based on some experiments in test tubes and mice.

Even one of Duke’s scientists urged caution. Darell Bigner, director of the Preston Robert Tisch Brain Tumor Center at Duke, told Pelley he’s optimistic that years of science may finally be coming together for glioblastoma patients, a sentiment he called “enormous.” But, he added, “I have to be very careful. I never want to give anyone false hope.”